1. Field of the Invention
This invention relates generally to printers and particularly to plotter-printers capable of printing graphic information. More specifically, the present invention relates to plotter-printers including a plurality of pens, preferably different in color or kind, which are selectively used to print desired information, such as characters, graphs and pictures, on recording paper on a platen.
2. Description of the Prior Art
A plotter-printer capable of printing character information as well as graphic information is well known in the art. In such a plotter-printer, typically, a plurality of pens, such as ball-point pens, are provided with their front or ball-point ends directed toward and separated away from a platen on which recording paper is placed. Such a prior art plotter-printer is illustrated in FIG. 1. As shown, the illustrated plotter-printer includes a plurality of pens 2 arranged in two rows, top and bottom, along the longitudinal axis of platen. The plotter-printer also includes a like plurality of actuating levers 6 pivotally supported on a carriage 4 and a like plurality of solenoids 8 fixedly mounted on the carriage 4. Thus, for each of the pens 2, provision is made of a unique actuating lever 6 and a unique solenoid 8. With such a structure, however, if it is desired to provide the increased number of pens, the carriage 4 necessarily becomes larger in size and weight, which could cause a deterioration in printing quality and slow down the printing speed. Besides, the printer as a whole tends to become larger in size and weight.